Apex domains cannot have CNAME records.
Question and response
Question
dig yournetbook.com. NS
Answer
yournetbook.com. 1 NS ns-740.awsdns-28.net.
yournetbook.com. 1 NS ns-486.awsdns-60.com.
yournetbook.com. 1 NS ns-1397.awsdns-46.org.
yournetbook.com. 1 NS ns-1023.awsdns-63.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0